A New Jersey police detective has been indicted on a first-degree murder charge in the shooting of another driver in a case of road rage in Maryland.

An Anne Arundel County grand jury returned the indictment Friday against 40-year-old Joseph Walker of Mount Holly.

Walker works for the Hudson County Prosecutor’s Office. He had been charged with second-degree murder and manslaughter immediately after the June 8 fatal shooting of Joseph Harvey Jr. of Millersville.

Authorities say Walker’s minivan cut off a car driven by Harvey. Harvey’s passenger told police that Walker pointed a gun at them. The drivers got out on a ramp, and the passenger says he heard shots. Harvey died at a hospital.